Induced proton transfer in an adduct of squaric acid and bipyridine

Consider the equilibrium between As[CH(SiMe3)2]2 and As2[CH(SiMe3)2]4. How might you gain insight into the position of this equilibrium in gas, liquid (solution) and crystalline phases by the use of NMR and EPR spectroscopy  

14 Induced proton transfer in an adduct of squaric acid and bipyridine 

The study was therefore pursued using high-resolution powder neutron diffraction, but during the required 12-hour data collection time the sample reacted with the vanadium sample can, and no useful structural information could be obtained. A high-flux neutron powder instmment was then used and the required data 

Comparison of form I (298 K, light grey) and form II (453 K, dark grey) SQBP. The calculation of the slipping angle was based on the intercept of the lines shown. Taken from [91] with permission of The Royal Society of Chemistry. 

Suggest possible crystal structures for the two higher pressure polymorphs of SQBP. How might you characterize them  

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